callerSaves, callerSaveVolatileRegs, get_GlobalReg_addr,
cmmAndWord, cmmOrWord, cmmNegate, cmmEqWord, cmmNeWord,
- cmmUGtWord,
+ cmmUGtWord, cmmSubWord, cmmMulWord, cmmAddWord, cmmUShrWord,
cmmOffsetExprW, cmmOffsetExprB,
cmmRegOffW, cmmRegOffB,
cmmLabelOffW, cmmLabelOffB,
-----------------------
cmmULtWord, cmmUGeWord, cmmUGtWord, cmmSubWord,
- cmmNeWord, cmmEqWord, cmmOrWord, cmmAndWord
+ cmmNeWord, cmmEqWord, cmmOrWord, cmmAndWord,
+ cmmUShrWord, cmmAddWord, cmmMulWord
:: CmmExpr -> CmmExpr -> CmmExpr
cmmOrWord e1 e2 = CmmMachOp mo_wordOr [e1, e2]
cmmAndWord e1 e2 = CmmMachOp mo_wordAnd [e1, e2]
cmmUGeWord e1 e2 = CmmMachOp mo_wordUGe [e1, e2]
cmmUGtWord e1 e2 = CmmMachOp mo_wordUGt [e1, e2]
--cmmShlWord e1 e2 = CmmMachOp mo_wordShl [e1, e2]
---cmmUShrWord e1 e2 = CmmMachOp mo_wordUShr [e1, e2]
+cmmUShrWord e1 e2 = CmmMachOp mo_wordUShr [e1, e2]
+cmmAddWord e1 e2 = CmmMachOp mo_wordAdd [e1, e2]
cmmSubWord e1 e2 = CmmMachOp mo_wordSub [e1, e2]
+cmmMulWord e1 e2 = CmmMachOp mo_wordMul [e1, e2]
cmmNegate :: CmmExpr -> CmmExpr
cmmNegate (CmmLit (CmmInt n rep)) = CmmLit (CmmInt (-n) rep)
-- * Regs.h claims that BaseReg should be saved last and loaded first
-- * This might not have been tickled before since BaseReg is callee save
-- * Regs.h saves SparkHd, ParkT1, SparkBase and SparkLim
--- EZY: This code is very dodgy, because callerSaves only ever
--- returns true in the current universe for registers NOT in
+--
+-- This code isn't actually used right now, because callerSaves
+-- only ever returns true in the current universe for registers NOT in
-- system_regs (just do a grep for CALLER_SAVES in
--- includes/stg/MachRegs.h). Thus, this is all one giant no-op. What we are
--- actually interested in is saving are the non-system registers, which
--- we is what the old code generator actually does at this point.
--- Unfortunately, we can't do that here either, because we don't
--- liveness information, and thus there's not an easy way to tell which
--- specific global registers need to be saved (the 'vols' argument in
--- the old code generator.) One possible hack is to save all of them
--- unconditionally, but unless we have very clever dead /memory/
--- elimination (unlikely), this will still leave a dead, unnecessary
--- memory assignment. And really, we shouldn't be doing the workaround
--- at this point in the pipeline, see Note [Register parameter passing].
--- Right now the workaround is to avoid inlining across unsafe foreign
--- calls in rewriteAssignments.
+-- includes/stg/MachRegs.h). It's all one giant no-op, and for
+-- good reason: having to save system registers on every foreign call
+-- would be very expensive, so we avoid assigning them to those
+-- registers when we add support for an architecture.
+--
+-- Note that the old code generator actually does more work here: it
+-- also saves other global registers. We can't (nor want) to do that
+-- here, as we don't have liveness information. And really, we
+-- shouldn't be doing the workaround at this point in the pipeline, see
+-- Note [Register parameter passing] and the ToDo on CmmCall in
+-- cmm/CmmNode.hs. Right now the workaround is to avoid inlining across
+-- unsafe foreign calls in rewriteAssignments, but this is strictly
+-- temporary.
callerSaveVolatileRegs :: (CmmAGraph, CmmAGraph)
callerSaveVolatileRegs = (caller_save, caller_load)
where
-------------------------------------------------------------------------
assignTemp :: CmmExpr -> FCode LocalReg
--- Make sure the argument is in a local register
+-- Make sure the argument is in a local register.
+-- We don't bother being particularly aggressive with avoiding
+-- unnecessary local registers, since we can rely on a later
+-- optimization pass to inline as necessary (and skipping out
+-- on things like global registers can be a little dangerous
+-- due to them being trashed on foreign calls--though it means
+-- the optimization pass doesn't have to do as much work)
assignTemp (CmmReg (CmmLocal reg)) = return reg
assignTemp e = do { uniq <- newUnique
; let reg = LocalReg uniq (cmmExprType e)
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